1. Field of the Invention
The present invention relates to a connector for connecting each of a plurality of forked terminals to each of a plurality of conductors of a flat cable, such as a flexible printed circuit or a ribbon electric wire, which consists of a flexible insulating sheet and printed conductors or thin wire conductors spaced in parallel with each other on at regular intervals on the sheet.
2. Description of the Related Arts
In recent years, a flat cable 3 as shown in Figs. 13A and 13B has been proposed. The flat cable 3 comprises a flexible insulating sheet 1 and conductors 2 spaced at regular intervals on the upper surface of the flexible insulating sheet 1. The conductor 2 is set to be as fine as approximately 0.1 mm in its diameter. The interval between adjacent conductors 2 is set to be as small as approximately 0.8 mm. Accordingly, the flat cable 3 is preferably used as an internal wiring material of household electrical appliances such as a VCR, a video camera and the like, and office automation appliances which are desired to be thin and compact.
Each conductor 2 of the flat cable 3 is connected with a forked terminal formed by punching a conductive metal plate. FIG. 14 shows an example of a connector for connecting the conductor 2 of the flat cable 3 and the forked terminal 7 with each other.
In the connector 4, a plurality of slit-shaped terminal-receiving openings 6 are formed in a cubic insulating housing 5 made of synthetic resin. The slit-shaped terminal-receiving openings 6 are spaced from each other at regular intervals in the longitudinal direction of the housing 5. A forked terminal 7 is inserted into each terminal-receiving opening 6. A flat cable 3 and a slide member 8 are inserted into the space between a contact arm 7a of the terminal 7 and a positioning arm 7b thereof to allow a pressing portion 8a of the slide member 8 to press the flat cable 3 against the contact arm 7a.
In the above-described connector 4, an incomplete connection is likely to occur between the terminal 7 and the conductor 2 of the flat cable 3.
That is, the conductor 2 and the contact arm 7a of the terminal 7 are in contact with each other. But as described above, the diameter of the conductor 2 is very small and in addition, the contact arm 7a contacts the conductor 2 in a small area because the width of the contact arm 7a is equal to a small width of the terminal 7. Accordingly, if the interval between adjacent terminals 7 does not coincide with that between adjacent conductors 2 or if the intervals between adjacent conductors 2 are nonuniform or if the intervals between adjacent terminals 7 are nonuniform, an incomplete connection is likely to occur between the conductor 2 and the terminal 7.
The contact arm 7a of the terminal 7 and the positioning arm 7b thereof are inserted into each of openings 6a of the terminal-receiving opening 6 and each of openings 6b thereof. The slide member 8 presses the flat cable 3 against the contact arm 7a, thus holds the flat cable 3 inside the housing 5. But the connector 4 has no means for placing the terminal 7 in position inside the housing 5. Therefore, it is likely that the terminals 7 are inserted at different positions inside the housing 5. As a result, the flat cable 3 is pressed against the terminals 7 at different pressures.
The slide member 8 is installed in the housing 5 in the direction in which the openings 6 are arranged from the side opposite to the terminal-inserting side. Each of a pair of holding portions 8b projecting from each end of the slide member 8 in the longitudinal direction thereof is fixed to each end of the housing 4 disposed in the longitudinal direction thereof.
In recent years, the connector 4 has become longer owing to the increase in the number of the openings 6 to be formed in parallel with each other in the housing 5 caused by demands for multipolarization. Hence, the slide member 8 has become longer.
As a result, it is likely that the pressing portion 8a comprising thin plates disposed between both holding portions 8b are flexed as shown in FIGS. 15A and 15B.
The pressing portion 8a presses the conductors 2 of the flat cable 3 against the terminal 7. Therefore, when the pressing portions 8a is flexed, there is a possibility that pressures applied by the pressing portion 8a to the conductors 2 are different from each other depending on the flexure degree of the pressing portion 8a or some conductors 2 are not brought into contact with the corresponding terminal 7.
Insulating resin is integrally molded by a mold to form the slide member 8. Upon completion of molding, the molded insulating resin is ejected by an ejector pin from the mold. It is necessary to form a portion to be ejected by the ejector on both holding portions 8b. Due to the ejection of the molded insulating resin, a burr (B) is formed on the ejected portion. The burr (B) projecting from the surface of the holding portions 8b prevents the slide member 8 from closely contacting the housing 5. As a result, there is a possibility that the loose contact between the housing 5 and the slide member 8 prevents the conductor 2 from being appropriately pressed against the terminal 7. The burr (B) can be removed from the slide member 8 by polishing it, but it takes time and labor, which causes the connector 4 to be manufactured at a high cost.
Referring to FIGS. 16 and 17, the case in which the connector 4 is soldered to a base plate 9 is considered below.
The connector 4 shown in FIG. 16 is soldered by using a U-shaped holder 101 as follows: The holder 101 comprises an upper holding portion 101a disposed on the upper surface of the housing 5, a lower holding portion 101b disposed on the lower surface thereof, and a side holding portion 101c disposed on the side surface thereof. The holder 101 is fixed to both sides of the housing 5, and the lower holding portion 101b of the holder 101 is soldered to a pad 9a disposed on a base plate 9. In this manner, the housing 5 is fixed to the base plate 9.
The connector 4 shown in FIG. 17 is soldered by using a U-shaped holder 101' as follows: The holder 101' is engaged by a U-shaped engaging groove 5'a formed in the vicinity of both side surfaces of a housing 5'. A lower holding portion 101'b of the holder 101' is soldered to the pad 9a disposed on the base plate 9. In this manner, the housing 5' is fixed to the base plate 9.
In the connector shown in FIG. 16, the lower holding portion 101b of the holder 101 is disposed on the lower surface of the housing 5, i.e., the lower holding portion 101b is interposed between the lower surface of the housing 5 and the pad 9a. Therefore, the lower surface of the housing 5 is not in close contact with the base plate 9 and hence the housing 5 cannot be tightly fixed to the base plate 9.
The holder 101 is installed on both side surfaces of the housing 5. So long as the holding portion 8b of the holder 8 is mounted on the side surfaces of the housing 5, it is difficult to install the holder 101 on the side surfaces of the housing 5 with respect to the size of the side surface of the housing 5.
In the connector shown in FIG. 17, the holder 101' is thin. Therefore, the holder 101' is soldered to the pad 9a in a small area and thus there is a possibility that the holder 101' is fixed thereto not in a high strength. If the holder 101' is made to be thick, it is necessary to make the width of the engaging groove 5'a large. Consequently, the housing 5' becomes large. If the housing 5' is not made to be large, the terminal-receiving openings are decreasingly formed inside the housing 101'. In addition, the holder 101' is fixed to the housing 5' by engaging the housing 5' with the engaging groove 5'a of the housing 5'. Therefore, the holder 101' is not tightly fixed to the housing 5'.
Referring to FIG. 18, in installing the connector 4 on the base plate 9 by an automatic machine, both side surfaces 5c and 5d of the housing 5 are sandwiched by arms 102a and 102b of a chuck 102 of the automatic machine. In this state, the center L1 of the chuck 102 and the center L2 of the housing 5 coincide with each other. Therefore, a connector-installing position (X) with which the center L2 of the housing 5 should be coincident is set on the base plate 9 so that the center L1 of the chuck 102 is made to be coincident with the connector-installing position (X). In this manner, the housing 5 is held by the chuck 2. Then, the chuck 102 is moved downward as shown by an arrow (A) of FIG. 19 and the housing 5 is soldered to the pad placed on the base plate 9.
As described previously, the demand for multipolarization of the connector 4 causes the housing 5 to be long in the direction (W) in which the terminal-receiving openings 6 are arranged in parallel with each other. It is necessary to set the side surface 5d of the housing 5 at a gate position (G) corresponding to a resin-injecting opening of the mold and inject resin into the mold from the gate position (G) so as to flow the resin smoothly in the mold in the direction corresponding to the longitudinal direction of the housing 5.
A gate remainder 103 is likely to be formed in the gate position (G) as shown in FIG. 19. The side surface 5d on which the gate position (G) is formed is held by the chuck 102. Therefore, the center L1 of the chuck 102 and the center L2 of the housing 5 do not coincide with each other due to the existence of the gate remainder 103 when the housing 5 is held by the chuck 102. When the center L1 of the chuck 102 is made to be coincident with the connector-installing position (X) of the base plate 9, the center L2 of the housing 5 does not coincide with the connector-installing position (X). That is, the housing 5 cannot be placed exactly in position on the base plate 9.
After the gate remainder 103 is removed from the gate position (G), the housing 5 can be placed exactly in position on the base plate 9 by the chuck 102 which holds the housing 5. But it is necessary to check whether or not the gate remainder 103 exists on the gate position (G) after the housing 5 has been molded. In addition, it is difficult and inefficient to remove the gate remainder 103 from the gate position (G).
When the housing 5 is to be installed on the base plate 9, the terminals 7 and the slide member 8 have been already installed widthwise in the housing 5. Therefore, it is difficult for the arms 102a and 102b of the chuck 102 to hold the housing 5 widthwise. Therefore, the side surfaces 5c and 5d cannot be taken hold of by the arms 102a and 102b of the chuck 102.